Fern Acres, HI has a population of 1,392 and is the 13,126th largest city in the United States. The population density is 204 per sq mi which is 61% higher than the Hawaii average and 126% higher than the national average. The median age in Fern Acres is 49 which is approximately 27% higher than the Hawaii average of 39. In Fern Acres, 61% of the population over 15 years of age are married, 87% speak English and 0% speak Spanish. 54% of Fern Acres residents were born in Hawaii, 28% were born out of state, 2% were born outside of the United States and 17% were foreign born.